BRAKING SYSTEM FOR VEHICLES
FIELD OF THE TECHNOLOGY
[OOOI] The present invention relates to braking system for vehicles, and, more
particularly, to a synchronous braking system for the vehicles.
BACKGROUND
[0002] Generally, two-wheeled and three-wheeled vehicles are equipped with
separate brake actuating means for the front and rear wheels. For example, a
hand lever mounted on the handle bar actuates the front wheel brake assembly
and a foot pedal or another hand lever actuates the rear wheel brake assembly. A
rider decelerates or stops a vehicle by operating the front and rear wheel brake
actuating means independently. The independently operated front and rear brake
actuating means trigger the front or rear wheel brake assemblies by means of
separate respective cables.
[0003] However, in emergency situations, such arrangements constitute a
safety issue as the optimum use of front and rear brakes without wheel locking of
front or rear wheels depend on the judgment of a rider. To obviate these issues,
attempts have been made to devise a synchronous braking system whereby any
single brake actuating means (hand lever or foot pedal) actuate the front and rear
wheel brake assemblies simultaneously.
[0004] United States Patent 4208074 titled "Hydraulic Pressure Control
Systemn discloses a hydraulic pressure control system for brakes for use within
motor vehicles that includes a split or dual type braking system having two brake
lines. A metering valve is disposed within the front brake line so as to delay the
build-up of pressure within the front disc brakes for a predetermined period of
time. Similarly, a pressure-control valve is disposed within the rear brake line for
supplying a controlled or limited fluid pressure to the rear wheel brakes from the
2
rear brake valve includes a spring guide and a valve return spring disposed
between the bonded valve and the spring guide to exert a force on the bonded
valve to bias it upwardly. The bonded valve is configured to reciprocate with
respect to the spring guide. Furthermore, the rear brake valve includes an
intermediate wall, where the rear brake valve is configured to propagate fluid
pressure from the rear brake master cylinder to the rear wheel brake assembly.
Furthermore, an upward movement of the bonded valve of the rear brake valve
under the fluid pressure and force of valve return spring is restricted when the
fluid pressure at the inlet opening of the rear brake valve is equal or above a predetermined
value of the fluid pressure. The pre-determined value of the fluid
pressure is pressure just below the prassure at which rotary motion of a rear
wheel locks.
. [0012] In an embodiment, the integrated brake valve includes a first section
having a first section inlet opening fluidically connected to the rear brake master
cylinder and a second section having a second section inlet opening fluidically
connected to the front brake master cylihder. The integrated brake valve further
includes a communication gallery and an outlet opening fluidically connected to
the front wheel brake assembly. The first section and the second section are
fluidically connected through the communication gallery. The first section includes
a first section bonded valve and a non return valve. The first section bonded valve
is received by a first section valve guide and is configured to reciprocate therein.
The first section also includes a first section elastic member having lower end
supported and guided by the first section valve guide and an upper end supported
and guided by the first section bonded valve. The first section elastic member is
configured to exert a force to bias the first section bonded valve upwardly. The
second section includes an integrated valve piston. The integrated valve piston is
configured to reciprocate along a length direction within the second section of the
integrated brake valve.
[0013] In addition, the second section includes two seal members fixed on
each side of the outlet opening of the integrated brake valve to restrict the
integrated valve piston under the fluid pressure. Moreover, the second section
includes at least one first drill hole that open into the outlet opening and a portion
of the second section that is towards the communication gallery and at least one
second drill hole that opens into the outlet opening and a portion of the second
section that is away from the communication gallery.
[0014] In an embodiment, the non return valve is configured to block the fluid
pressure to propagate from the first section inlet opening to the communication
gallery through an opening of the non return valve. The first section bonded valve
is configured to not deflect till the fluid pressure at the first section inlet opening is
less than the predetermined value of the fluid pressure and thereafter is
configured to propagate fluid pressure from the rear brake master cylinder to the
front wheel brake assembly. The elastic constant of the elastic body of the rear
brake valve and the elastic constant of the first section elastic member are same.
The integrated valve piston is configured to move in one of a left direction and a
right direction when there is a difference in the fluid pressure applied by the rear
brake master cylinder to a side of the integrated valve piston that is towards the
first section and the fluid pressure applied by the front brake master cylinder to a
side of the integrated valve piston that is towards the second section inlet
opening.
[0015] In an embodiment, the integrated brake valve is configured to transfer
fluid pressure to the front wheel brake assembly when the rear brake master
cylinder applies more pressure than a pre-determined value of fluid pressure. In
an embodiment, the bonded valve touches an intermediate wall of the rear brake
valve and an upward movement of the bonded valve is restricted hence the fluid
pressure propagated on the rear wheel brake assembly is less than a limiting
pressure at which motion of rear wheel locks.
[0016] In an embodiment, the fluid pressure at a first section inlet opening
decreases and when it is less than the pre-determined value, a first section
bonded valve abuts against the first section wall member of the integrated brake
valve and fluid communication through the first section bonded valve is stopped
and the residual fluid pressure is released through the non return valve depending
upon pressure difference on opposite sides of the non return valve. Moreover, the
fluid pressure is applied to the front wheel brake assembly when an operator
actuates the front wheel brake actuating means.
[0017] In an embodiment, the front wheel brake assembly is configured to be
actuated by a maximum of a fluid pressure among the fluid pressure applied from
the rear brake master cylinder and a fluid pressure applied from the front brake
master cylinder when both of the front wheel brake actuating means and the rear
wheel brake actuating means are actuated and the fluid pressure applied by the
rear brake master cylinder is more than the predetermined value.
[0018] In an embodiment, if both of the front wheel brake actuating means and
the rear wheel brake actuating means are actuated and if the fluid pressure
applied by the rear brake master cylinder is more than the pre-determined value
and if the fluid pressure on a side of the integrated valve piston that is towards the
first section is more than the fluid pressure on a side of the integrated valve piston
that is towards the second section inlet opening, the integrated valve piston
deflects in a direction towards the second section inlet opening and the fluid
pressure applied by the rear brake master cylinder is transferred through the first
section inlet opening then through the first section bonded valve then through the
outlet opening to the front wheel brake assembly.
[0019] In an embodiment, if both of the front wheel brake actuating means and
the rear wheel brake actuating means are actuated and if the fluid pressure on a
side of the integrated valve piston that is towards the second section inlet opening
is more than the fluid pressure on a side of the integrated valve piston that is
towards the first section, the integrated valve piston deflects in a direction towards
the first section and the fluid pressure applied by the front brake master cylinder is
transferred through the second section inlet opening and then through the outlet
opening of the integrated brake valve to a wheel cylinder of the front wheel brake
assembly.
[0020] In an embodiment, the rear brake valve further comprises a first piece
and a second piece. The first piece is configured to confine the piston, the elastic
body and configured to form the outlet opening. The second piece is configured to
confine the bonded valve, the spring guide, the valve return spring and is
configured to form an inlet opening. In an embodiment, a plate member is
provided at the upper end of the elastic body. The plate member is configured to
be movable in vertical direction with the help of an adjusting screw member.
[0021] Other aspects and exemplary embodiments are provided in the
drawings and the detailed description that follows.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0022] The invention itself, together with further features and attended
advantages, will become apparent from consideration of the following detailed
description, taken in conjunction with the accompanying drawings. One or more
embodiments of the present invention are now described, by way of example
only, with reference to the accompanied drawings wherein like reference
numerals represent like elements and in which:
[0023] Figure 1 illustrates a block diagram of a braking system according to an
embodiment of the present invention;
[0024] Figure 2 illustrates a sectional view of a rear brake valve according to
an embodiment of the present invention;
[0025] Figure 3 illustrates a sectional view of an integrated brake valve
according to an embodiment of the present invention;
[0026] Figure 4 illustrates an arrangement when only a rear brake master
cylinder is actuated and applied fluid pressure is less than a pre-determined value
according to an embodiment of the present invention;
[0027] Figure 5 illustrates an arrangement when only the rear brake master
cylinder is actuated and applied fluid pressure is equal to or more than the predetermined
value according to an embodiment of the present invention;
[0028] Figure 6 illustrates an arrangement when a rear wheel brake actuating
means is released according to an embodiment of the present invention;
[0029] Figure 7 illustrates an arrangement when only a front brake master
cylinder is actuated according to an embodiment of the present invention;
[0030] Figure 8 illustrates an arrangement when the front and rear brake
master cylinders are actuated and the pressure exerted by the rear brake master
cylinder is more than the pre-determined value and more than the front brake
master cylinder according to an embodiment of the present invention;
[0031] Figure 9 illustrates an arrangement when the front and rear brake
master cylinders are actuated and fluid pressure exerted by the rear brake master
cylinder is more than the pre-determined value and less than the front brake
master cylinder according to an embodiment of the present invention; and
[0032] Figure 10 illustrates a rear brake valve according to an embodiment of
the present invention.
[0033] The drawings referred to in this description are not to be understood as
being drawn to scale except if specifically noted, and such drawings are only
exemplary in nature.
DETAILED DESCRIPTION OF ACCOMPANYING DRAWINGS AND THE
PREFFERED EMBODIMENT
[0034] While the invention is susceptible to various modifications and
alternative forms, specific embodiment thereof has been shown by way of
example in the drawings and will be described in detail below. It should be
understood, however that it is not intended to limit the invention to the particular
forms disclosed, but on the contrary, the invention is to cover all modifications,
equivalents, and alternative falling within the spirit and the scope of the invention.
[0035] The terms "comprisesn, "comprisingn, or any other variations thereof,
are intended to cover a non-exclusive inclusion, such that a setup, device or
method that comprises a list of components or steps does not include only those
components or steps but may include other components or steps not expressly
listed or inherent to such setup or device or method. In other words, one or more
elements in a system or apparatus proceeded by "comprises ... a" does not,
without more constraints, preclude the existence of other elements or additional
elements in the system or apparatus.
[0036] In. accordance with the present invention the drawbacks as stated
hereinabove have been overcome by providing a system that limits a maximum
pressure being applied to a rear wheel brake assembly so as to avoid locking of a
rear wheel, also, to provide a system that transfers pressure to a front wheel
brake assembly once a pre-determined value of braking pressure limit of the rear
wheel brake assembly is reached so as to achieve efficient overall braking
system. Further, the system is capable of deciding whether a front wheel brake
assembly should be applied with the actual pressure desired and actuated by the
rider 1 operator using a front wheel brake actuating means or by the pressure
actuated by the rider 1 operator using a rear wheel brake actuating means. It may
also be noted that herein the present description, the terms 'rider' and 'operator'
are used interchangeably and refers to a person who will ride on the vehicle.
[0037] For the better understanding of this invention, reference would now be
made to the embodiment illustrated in greater depth in the accompanying figures
and description herebelow, further,. in the following figures, the same reference
numerals are used to identify the same components in various views. The
orientation of the components illustrated in the figures is for the references and
description purpose only and is not intended to limit the invention to the particular
orientation disclosed.
[0038] Figure 1 illustrates an overall braking system (100) for a two-wheeled or
a three-wheeled vehicle, in accordance with an embodiment of the present
invention. The two-wheeled or three-wheeled vehicle has separate brake
actuating means to actuate the front and rear brake assemblies. It may be noted
that the terms 'two-wheeled vehicle', 'three-wheeled vehicle' are hereinafter
interchangeably referred to as 'vehicle' in the present description.
[0039] Referring to Figure I, the braking system (100) comprises a front wheel
(I), a rear wheel (2), a front wheel brake assembly (3), a rear wheel brake
assembly (4), a front wheel brake actuating means (5), a rear wheel brake
actuating means (6), a rear brake valve (7), an integrated brake valve (8), a front
brake master cylinder (9) and a rear brake master cylinder (10). Example of the
front wheel brake actuating means (5) includes, but is not limited to, a hand lever.
Example of the rear wheel brake actuating means (6) includes, but is not limited
to, a foot pedal.
[0040] The rear brake valve (7) has an inlet opening (7i) fluidically connected
to the rear brake master cylinder (10) and an outlet opening (70) fluidically
connected to a wheel cylinder of the rear wheel brake assembly (4). The
integrated brake valve (8) has two inlet openings: a first section inlet opening (81 i)
and a second section inlet opening (82i). The first section inlet opening (81i) is
fluidically connected to the rear brake master cylinder (1 0) and the second section
inlet opening (82i) is fluidically connected to the front brake master cylinder (9).
An outlet opening (80) of the integrated brake valve (8) is fluidically connected to
a wheel cylinder of the front wheel brake assembly (3) of the front wheel (1).
[0041] Figure 2 illustrates the rear brake valve (7), in accordance with an
embodiment of the present invention. The rear brake valve (7) includes a
cylindrical wall body (7w). The cylindrical wall body (7w) is closed from the top
and has the inlet opening (7i) and the outlet opening (70) on the cylindrical wall
body (7w). Further, the rear brake valve (7) includes a piston (II), the cylindrical
wall body (7w) is adapted to receive the piston (1 1). The piston (1 1) is adapted to
reciprocate along a vertical axis of the rear brake valve (7), if the rear brake valve
(7) has a vertical orientation. It should be noted that if the rear brake valve (7) is
placed horizontally, then this axis would be a horizontal axis, similar logic may be
extended for any other orientation. An upper end (I lu) of the piston (1 1) is near
to a closed top end of the rear brake valve (7) and forms a circular recess ( I I r). In
addition, an elastic body (12) is confined in the circular recess (I lr) of the piston
(1 1) at its lower end and by an inner top end of the rear brake valve (7) at its
upper end. The piston (1 1) is adapted to remain downwardly biased under the
force of the elastic body (12). Examples of the elastic body (12) include, but may
not be limited to, a pressure setting spring.
[0042] The piston (1 1) at its lower end (1 11) abuts against a bonded valve (1 3).
A spring guide (14) is adapted to receive the bonded valve (13). In addition, the
bonded valve (13) is adapted to reciprocate with respect to the spring guide (14).
The spring guide (14) with the help of o-ring forms the bottom closing end of the
rear brake valve (7). Normally, the bonded valve (13) is upwardly biased under
the force of a valve return spring (15) which is disposed between the bonded
valve (1 3) and the spring guide (14).
[0043] Now, referring to Figure 4 (also in conjunction with Figure 2), when the
rear wheel brake actuating means (6), such as a foot pedal, is pressed by a rider,
the rear brake master cylinder (10) is fluidically actuated, and the fluid pressure
builds up at the inlet opening (7i) of the rear brake valve (7), thereby creating an
upward force on the lower end (1 11) of the piston (1 1). The piston (1 1) lifts up
against the downward force of the elastic body (12). At the same time, the bonded
valve (13) also lifts up under the upward force of the fluid pressure and the force
of the valve return spring (1 5).
I00441 Thus, the fluid pressure propagates from the inlet opening (7i) to the
outlet opening (70) of the rear brake valve (7) which further propagates to the
wheel cylinder of the rear wheel brake assembly (4) that decelerates 1 stops the
motion of the rear wheel (2). In an embodiment, the location of the inlet opening
(7i) is selected with respect to the bonded valve (13) such that the fluid pressure
does not deflect the bonded valve (13) downwardly when the piston (1 1) is lifted
upwardly. The bonded valve (13) and the piston (11) always remain abuttingly
configured against each other for any value of fluid pressure.
[0045] Referring to Figure 5, as the rider applies more pressure, the piston
(1 1) and the bonded valve (13) deflects upwardly. When the fluid pressure at the
inlet opening (7i) of the rear brake valve (7) is equal or above a predetermined
value, the bonded valve (13) touches an intermediate wall (16). When the piston
(1 1) and the bonded valve (13) are at their maximum lifted position, the further
upward movement of the bonded valve (13) restricts. As the movement of the
bonded valve (13) restricts, it also restricts the fluid to create any further fluid
pressure on the lower end (1 I I) of the piston (1 1). Hence, no further fluid pressure
is transferred to the rear wheel brake assembly (4). This implies that the fluid
pressure on the rear wheel brake assembly (4) cannot be more than a limiting
13
pressure at which the rear wheel (2) motion locks. This ensures that the rear
wheel (2) does not skid, thereby enhancing the safety.
[0046] In an embodiment, a combined elastic constant of the elastic body (12)
(such as pressure setting spring) and the valve return spring (15) of the rear
brake valve (7) is selected based on the weight of the piston (1 I), the bonded
valve (13) and frictional forces applicable therein. The combined elastic constant
is selected such that the bonded valve (1 3) touches the intermediate wall (16) and
seals the boundaries at the pre-determined value of the fluid pressure at the inlet
opening (7i). In an embodiment, the pre-determined value of the fluid pressure
may be a level of pressure which is just less than the limiting pressure at which
rotary motion of the rear wheel (2) locks.
[0047] When the rider releases the rear wheel brake actuating means (6), the
rear brake master cylinder (10) exerts lesser fluid pressure. The fluid pressure at
the inlet opening (7i) of the rear brake valve (7) decreases. When the fluid
pressure at the inlet opening (7i) is less than the pre-determined value, the
bonded valve (13) and the piston (1 1) start moving downward under the force of
the elastic body (12). Thus, the fluid pressure at the outlet opening (70) and the
inlet opening (7i) is less than the predetermined value.
[0048] Figure 3 illustrates the integrated brake valve (8), in accordance with an
embodiment of the present invention. The integrated brake valve (8) has two
sections: a first section and a second section indicated by the reference numerals
(81) and (8r), respectively. The first section (81) and the second section (8r) are
fluidically connected with each other through a communication gallery (17).
[0049] The first section (81) is closed by a first section valve guide (19) at
bottom end with the help of o-ring and has the first section inlet opening (81i).
Further, the first section (81) includes a first section bonded valve (20), which is
received by the first section valve guide (19) at its lower end and is adapted to
14
vertically reciprocate therein. It should be noted that if the integrated brake valve
(8) is placed in an orientation other than as depicted in the corresponding figures
(for example, Figure 3), then the direction of reciprocal motion of the first section
bonded valve (20) should be construed accordingly. A first section elastic member
(21) such as a pressure spring is disposed having its lower end supported and
guided externally by the first section valve guide (19) and the upper end
supported and guided externally by the first section bonded valve (20). Normally,
the first section bonded valve (20) is upwardly biased under the force of the first
section elastic member (21) and abuts against a first section wall member (22) of
the integrated brake valve (8).
[0050] In addition, a non return valve (23) is disposed in the first section (81) of
the integrated brake valve (8). The non return valve (23) includes a valve seat
member (24) having an opening (240) therethrough such that the cross sectional
area at the lower end of the valve seat member (24) is less than the cross
sectional area at its upper end.
[0051] A guide member (25) is confined in the opening (240) of the non return
valve (23). The non return valve (23) is biased downwardly under the force of a
non return valve elastic member (26). An upper end of the non return valve elastic
member (26) is supported by the body of the first section (81) or by the valve seat
member (24). The lower end of the non return valve elastic member (26) is
supported by the guide member (25).
. [0052] At one end, the second section (8r) of the integrated brake valve (8) is
fluidically connected to the communication gallery (17). At the other end, the
second section inlet opening (82i) is fluidically connected to the front brake
master cylinder (9). Also, the second section (8r) has the outlet opening (80)
which is fluidically connected to the wheel cylinder of the front wheel brake
assembly (3). Further, the second section (8r) of the integrated brake valve (8)
includes an integrated valve piston (27) which is free to reciprocate horizontally
within the second section (8r) of the integrated brake valve (8). It should be noted
that if the integrated brake valve (8) is placed in an orientation other than as
depicted in the corresponding figures (for example, Figure 3), then the direction of
reciprocal motion of the integrated valve piston (27) should be construed
accordingly. In an embodiment, the outlet opening (80) (as depicted in Figure 3) is
perpendicular to the reciprocal motion of the integrated valve piston (27). In
addition, the length of the integrated valve piston (27) or dimension along its
reciprocal motion is maintained more than the diameter of the outlet opening (80).
[0053] Also, on either side of the outlet opening (80), two seal members (28)
and (29) are fixed to the second section (8r) to restrict the reciprocal motion of the
integrated valve piston (27) under fluid pressure. The seal members (28) and (29)
are disposed such that the integrated valve piston (27) does not affect the
response time. In an embodiment, the seal members (28) and (29) are disposed
at a distance from the outlet opening (80) so that when the piston (27) touches
either of the seal member (28) or (29), it does not overlap with the outlet opening
(80).
[0054] Further, at least one first drill hole (30) is provided that opens into the
outlet opening (80) and a portion of the second section (8r) of the integrated
brake valve (8) that is towards the communication gallery (17). Further, at least
one second drill hole (31) is provided that opens into the outlet opening (80) and a
portion of the second section (8r) of the integrated brake valve (8) that is away
from the communication gallery (17). The first drill hole (30) and the second drill
hole (31) help to enhance the response time.
[0055] As illustrated in Figure 5, when the rider presses the rear wheel brake
actuating means (6) only (such as foot pedal alone), the rear brake master
cylinder (10) actuates fluidically and when the fluid pressure at the inlet opening
(7i) of the rear brake valve (7) is equal or above the pre-determined value, the
bonded valve (13) touches the intermediate wall (16) of the rear brake valve (7)
and further upward movement of the bonded valve (13) is restricted which
restricts the fluid to create any further pressure on the lower end (1 11) of the
piston (1 1). Hence, no further fluid pressure is transferred to the rear wheel brake
assembly (4) which implies that the fluid pressure on the rear wheel brake
assembly (4) cannot be more than the limiting pressure at which rear wheel
motion locks. As the pressure on the rear wheel brake assembly (4) cannot be
more than the limiting pressure at which the rear wheel (2) motion locks, the
chances of the skidding of the rear wheel (2) diminishes or reduces or eliminated.
At the same time, pressure at the first section inlet opening (81i) is same as that
of at the inlet opening (7i) of the rear brake valve (7). This pressure is being
continuously applied to a top surface (20t) of the first section bonded valve (20)
and the non return valve (23).
[0056] Because of its inbuilt characteristics, the non return valve (23) does not
allow (block) pressure to propagate from the first section inlet opening (81 i) to the
communication gallery (17) through the opening (240) of the non return valve
(23). In addition, the first section bonded valve (20) does not deflect till the fluid
pressure at the first section inlet opening (81i) is less than the pre-determined
value.
[0057] When the fluid pressure at the first section inlet opening (81i) is equal
or more than the pre-determined value, the first section bonded valve (20)
deflects downwardly proportional to the difference between forces, subject to
weight of the first section bonded valve (20) and frictional forces at the top surface
(20t) of the first section bonded valve (20) and force of the first section elastic
member (21). This deflection allows fluid pressure to propagate from the first
section inlet opening (81i) to the communication gallery (17), more particularly,
the deflection allows pressure to that surface (also referred to as a left surface of
the integrated valve piston (27)) of the integrated valve piston (27) which is
towards the first section (81).
[0058] Since only the rear wheel brake actuating means (6) is actuated, the
fluid pressure on the left side (as visible in Figure 5) of the integrated valve piston
(27) is more than the fluid pressure on its opposite side, hence, under the fluid
pressure, the integrated valve piston (27) deflects towards opposite side till its
motion is restricted by the seal member (28). Accordingly, the communication
gallery (17) enters into the fluid communication with the outlet opening (80),
thereby allowing pressure to be applied to the wheel cylinder of the front wheel
brake assembly (3) which is same as the fluid pressure created by the rear brake
master cylinder (10) or the fluid pressure at the first section inlet opening (81i) of
the integrated brake valve (8), to decelerate 1 stop the motion of the front wheel
(1 1.
[0059] Referring to Figure 6, when the rider releases the rear wheel brake
actuating means (6), the fluid pressure at the first section inlet opening (81i)
decreases, when the fluid pressure is less than the pre-determined value, the first
section bonded valve (20) again abuts against the first section wall member (22)
of the integrated brake valve (8). Accordingly, the fluid communication through the
first section bonded valve (20) cuts and the residual pressure is released through
the non return valve (23) depending upon the pressure difference on the opposite
sides of the non return valve (23).
[0060] Referring to Figure 7, when the rider actuates the front wheel brake
actuating means (5) only, the front brake master cylinder (9) actuates fluidically
and the fluid pressure builds up at the second section inlet opening (82i) of the
integrated brake valve (8). The fluid pressure on a surface (also referred to as a
right surface of the integrated valve piston (27)) of the integrated valve piston (27)
which is towards the second section inlet opening (82i) becomes more than the
fluid pressure on its opposite side (or the left surface of the integrated valve piston
(27)). Accordingly, under fluid pressure, the integrated valve piston (27) deflects
in a direction towards the left side till its motion is restricted by the seal member
(29). The second section inlet opening (82i) enters into the fluid communication
with the outlet opening (80), thus allowing fluid pressure to be applied to the
wheel cylinder of the front wheel brake assembly (3), which is same as fluid
pressure created by the front brake master cylinder (9), to decelerate / stop the
motion of the front wheel (1).
[0061] When the rider actuates both the brake actuating means (the rear
wheel brake actuating means (6) and the front wheel brake actuating means (5)
and if the fluid pressure applied by the rear brake master cylinder (10) is more
than the pre-determined value, the integrated valve piston (27) can move towards
the either of the directions depending upon the fluid pressure difference being
actuated on its left and right surfaces. In other words, when the fluid pressure
applied by the rear brake master cylinder (10) is being applied from the left side of
the integrated valve piston (27) (which is towards the first section (81)) and the
fluid pressure applied by the front brake master cylinder (9) is being applied from
the right side of the integrated valve piston (27) (which is towards the second
section inlet opening (82i)), the integrated valve piston (27) can move towards the
either of the directions depending upon the fluid pressure difference being
actuated from both sides.
[0062] In an embodiment, as illustrated in Figure 8, if the fluid pressure on the
left surface of the integrated valve piston (27) is more than the fluid pressure on
the right surface of the integrated valve piston (27), the integrated valve piston
(27) moves towards the right side (which is towards the second section inlet
opening (82i)), and then fluid pressure created by the rear brake master cylinder
(10) is transferred through the first section inlet opening (81i) then through the first
section bonded valve (20) then through the outlet opening (80) to the wheel
cylinder of the from wheel brake assembly (3). Further, as illustrated in the Figure
9, if the fluid pressure on the right surface of the integrated valve piston (27)
(which is towards the second section inlet opening (82i)) is more than the fluid
pressure on the left surface of the integrated valve piston (27) (which is towards
the first section (81)), the integrated valve piston (27) moves towards the left side
(which is towards the first section (81)), thereby the fluid pressure created by the
front brake master cylinder (9) is transferred through the second section inlet
opening (82i) then through the outlet opening (80) to the wheel cylinder of the
front wheel brake assembly (3).
[0063] Thus, when both the brake actuating means (5) and (6) are actuated
such that the rear wheel brake actuating means (6) is pressed to the extent that
fluid pressure applied by the rear brake master cylinder (10) is more than the predetermined
value, the front wheel brake assembly (3) is always actuated by the
maximum of the applied pressure by the rear brake master cylinder (10) and the
applied pressure by the front brake master cylinder (9). This ensures more safety
for the rider.
[0064] In an embodiment of the present invention, referring to Figure 10, the
rear brake valve (7) includes a first piece (70u) and a second piece (701). The first
piece (70u) and the second piece (701) are cylindrical wall bodies. The first piece
(70u) confines the piston (1 1) and the elastic body (12). In addition, the first piece
(70u) forms the outlet opening (70). The second piece (701) confines the bonded
valve (13), the spring guide (14), and the valve return spring (15). In addition, the
second piece (701) forms the inlet opening (7i).
[0065] In an embodiment of the present invention, referring to Figure 10, the
elastic body (12) at its upper end is supported by a plate member (70p) which in
turn is adapted to be movable in a vertical direction with the help of adjusting a
screw member (70s). By adjusting the screw member (70s) in vertical direction,
the plate member (70p) can also be moved. At the same time, the elastic constant
of the elastic body (12) can be adjusted. As already described hereinabove, the
pre-determined value of pressure is, inter alia, function of elastic constant of the
elastic body (12). The pre-determined value can be adjusted as per the
requirement by adjusting the screw member (70s).
[0066] In accordance with yet another embodiment, a similar mechanism (not
shown in the figures) to adjust the elastic constant for the first section elastic
member (21) can be devised.
[0067] In accordance to yet another embodiment of the invention, the first
section (81) and the second section (8r) of the integrated brake valve (8) are
attached together by means of fastening. Examples of means of fastening include
but may not be limited to bolts, and fasteners.
[0068] Without in any way limiting the scope, interpretation, or application of
the claims appearing below, advantages of one or more of the exemplary
embodiments disclosed include provision of braking system.
[0069] The braking system of the present invention is fluidically and has no
elements that necessitate electric 1 electronic components. The stated braking
system limits the maximum braking pressure to be applied to the rear wheel brake
assembly. Further, the braking system provides operatorlrider with an option to
operate the front wheel brake assembly and the rear wheel brake assembly as
per conventional independent braking system. The braking system transfers fluid
pressure to the front wheel brake assembly once a predetermined value of the
fluid pressure for the rear wheel brake assembly is reached. Furthermore, the
braking system applies fluid pressure to the front wheel brake assembly which is
more among the pressures actuated by the front wheel brake actuating means
such as hand lever or the pressure actuated by the rear wheel brake actuating
means such as foot pedal once the limiting pressure of the rear wheel brake
assembly is reached. Furthermore, the stated braking system is less complicated
and is cost effective.
[0070] While considerable emphasis has been placed herein on the particular
features of this invention, it will be appreciated that various modifications can be
made, and that many changes can be made in the preferred embodiments
without departing from the principles of the invention. These and other
modifications in the nature of the invention or the preferred embodiments will be
. apparent to those skilled in the art from the disclosure herein, whereby it is to be
distinctly understood that the foregoing descriptive matter is to be interpreted
merely as illustrative of the invention and not as a limitation.
CLAIMS
What is claimed is:
1. A braking system for a vehicle, the braking system comprising:
a rear brake master cylinder;
a rear brake valve fluidically connected to the rear brake master
cylinder;
a rear wheel brake assembly fluidically connected to the rear brake
valve;
a front brake master cylinder;
an integrated brake valve fluidically connected to the rear brake master
cylinder and fluidically connected to the front brake master cylinder; and
a front wheel brake assembly fluidically connected to the integrated
brake valve.
2. The braking system as claimed in claim 1, wherein:
a front wheel brake actuating means configured to actuate the front
brake master cylinder; and
a rear wheel brake actuating means configured to actuate the rear
brake master cylinder.
3. The braking system as claimed in claim 2, wherein the front wheel
brake actuating means and the rear wheel brake actuating means comprise
hand levers or foot pedals or a hand lever and a foot pedal.
4. The braking system as claimed in claims 1 or 2, wherein the rear brake
valve comprises:
a cylindrical wall body having an inlet opening fluidically connected to
the rear brake master cylinder and an outlet opening connected to the rear
wheel brake assembly;
a piston configured to reciprocate along an axis therewithin the
cylindrical wall body;
an elastic body configured to exert a force on the piston to bias it
downwardly;
a bonded valve, wherein a lower end of the piston abuts against the
bonded valve;
a spring guide, wherein the bonded valve is configured to reciprocate
with respect to the spring guide;
a valve return spring disposed between the bonded valve and the
spring guide to exert a force on the bonded valve to bias it upwardly; and
an intermediate wall,
wherein the rear brake valve is configured to propagate fluid pressure
from the rear brake master cylinder to the rear wheel brake assembly.
5. The braking system as claimed in claim 4, wherein an upward
movement of the bonded valve of the rear brake valve under the' fluid
pressure and force of the valve return spring is restricted when a fluid
pressure at the inlet opening of the rear brake valve is equal or above a predetermined
value of the fluid pressure.
6. The braking system as claimed in claim 5, wherein the pre-determined
value of the fluid pressure is a pressure just below the pressure at which
rotary motion of a rear wheel locks.
7. The braking system as claimed in claims 1 or 2 or 4, wherein the
integrated brake valve comprises:
a first section having a first section inlet opening fluidically connected
to the rear brake master cylinder;
a second section having a second section inlet opening fluidically
connected to the front brake master cylinder;
a communication gallery, wherein the first section and the second
section are fluidically connected through the communication gallery; and
an outlet opening fluidically connected to the front wheel brake
assembly.
8. The braking system as claimed in claim 7, wherein the first section
comprises:
a first section bonded valve received by a first section valve guide and
is configured to reciprocate therein;
a non return valve; and
a first section elastic member having lower end supported and guided
by the first section valve guide and an upper end supported and guided by
the first section bonded valve, the first section elastic member configured to
exert a force to bias the first section bonded valve upwardly.
9. The braking system as claimed in claim 7, wherein the second section
comprises an integrated valve piston to reciprocate along a length direction
within the second section of the integrated brake valve.
10. The braking system as claimed in claim 9, wherein the second section
comprises two seal members fixed on each side of the outlet opening of the
integrated brake valve to restrict the integrated valve piston under the fluid
pressure.
11. The braking system as claimed in claim 9, wherein the second section
comprises:
at least one first drill hole that opens into the outlet opening and a
portion of the second section that is towards the communication gallery; and
at least one second drill hole that opens into the outlet opening and a
portion of the second section that is away from the communication gallery.
12. The braking system as claimed in claim 8, wherein the non return valve
is configured to block the fluid pressure to propagate from the first section
inlet opening to the communication gallery through an opening of the non
return valve.
13. The braking system as claimed in claim 8, wherein the first section
bonded valve is configured to not deflect till the fluid pressure at the first
section inlet opening is less than a predetermined value of the fluid
pressure and thereafter is configured to propagate fluid pressure from the
rear brake master cylinder to the front wheel brake assembly.
14. The braking system as claimed in claim 8, wherein an elastic constant
of the elastic body of the rear brake valve and an elastic constant of the first
section elastic member are same.
15. The braking system as claimed in claim 9, wherein the integrated valve
piston is configured to move in one of a left direction and a right direction
when there is a difference in a fluid pressure applied by the rear brake
master cylinder to a side of the integrated valve piston that is towards the
first section and a fluid pressure applied by the front brake master cylinder to
a side of the integrated valve piston that is towards the second section inlet
opening.
16. The braking system as claimed in claims 1 or 4 or 7, wherein the
integrated brake valve is configured to transfer fluid pressure to the front
wheel brake assembly when the rear brake master cylinder applies more
pressure than a pre-determined value of fluid pressure.
17. The braking system as claimed in claim 5, wherein the bonded valve
touches an intermediate wall of the rear brake valve and an upward
movement of the bonded valve is restricted hence the fluid pressure
propagated on the rear wheel brake assembly is less than a limiting
pressure at which motion of a rear wheel locks.
2 6
18. The braking system as claimed in claims 8 or 16, wherein when the
fluid pressure at the first section inlet opening decreases and becomes less
than the pre-determined value, the first section bonded valve abuts against a
first section wall member of the integrated brake valve and a fluid
communication through the first section bonded valve is stopped and the
residual fluid pressure is released through the non return valve depending
upon pressure difference on opposite sides of the non return valve.
19. The braking system as claimed in claim 2, wherein the fluid pressure is
applied to the front wheel brake assembly when the operator actuates the
front wheel brake actuating means.
20. The braking system as claimed in claims 2 or 8, wherein the front
wheel brake assembly is configured to be actuated by a maximum of a fluid
pressure among a fluid pressure applied from the rear brake master cylinder
and a fluid pressure applied from the front brake master cylinder when both
of the front wheel brake actuating means and the rear wheel brake actuating
means are actuated and the fluid pressure applied by the rear brake master
cylinder is more than the predetermined value.
21. The braking system as claimed in claim 9, wherein if both of the front
wheel brake actuating means and the rear wheel brake actuating means are
actuated and if the fluid pressure applied by the rear brake master cylinder is
more than the pre-determined value and if the fluid pressure on a side of the
integrated valve piston that is towards the first section is more than the fluid
pressure on a side of the integrated valve piston that is towards the second
section inlet opening, the integrated valve piston deflects in a direction
towards the second section inlet opening and the fluid pressure applied by
the rear brake master cylinder is transferred through the first section inlet
opening then through the first section bonded valve then through the outlet
opening to the front wheel brake assembly.
22. The braking system as claimed in claim 9, wherein if both of the front
wheel brake actuating means and the rear wheel brake actuating means are
actuated and if the fluid pressure on a side of the integrated valve piston that
is towards the second section inlet opening is more than the fluid pressure
on a side of the integrated valve piston that is towards the first section, the
integrated valve piston deflects in a direction towards the first section and
the fluid pressure applied by the front brake master cylinder is transferred
through the second section inlet opening and then through the outlet
opening of the integrated brake valve to a wheel cylinder of the front wheel
brake assembly.
23. The braking system as claimed in claim 4, wherein the rear brake valve
comprises:
a first piece configured to confine the piston, the elastic body and is
configured to form the outlet opening; and
a second piece configured to confine the bonded valve, the spring
guide and the valve return spring and is configured to form the inlet opening,
and wherein the first piece and the second piece are cylindrical wall bodies.
24. The braking system as claimed in claim 4, wherein a plate member is
provided at an upper end of the elastic body, wherein the plate member is
6
configured to be movable in a vertical direction by an adjusting screw
member.